Solid rinse aids and methods of warewashing utilizing solid rinse aids

Abstract

Methods of warewashing utilizing a solid rinse aid, and the solid rinse aid which comprises a surfactant and urea, and preferably a dispensing rate adjusting additive, are disclosed.

We claim: 
     
       1. A method of warewashing, including at least a wash water cycle and a rinse water cycle, which comprises dispensing, in a rinse cycle, an effective amount of a surfactant from a water soluble solid block rinse aid said rinse aid consisting essentially of: (a) about 5-40% by weight urea;   (b) about 60-90% by weight of a polymeric synthetic organic surfactant having a molecular weight of about 700-14,000 comprising a polyethylene oxide block and a polypropylene oxide block; and   (c) sufficient water to provide a water:urea weight ratio of about 1:3 to 1:6.   
     
     
       2. The method of claim 1 wherein the solid block rinse aid comprises about 5-15% by weight urea. 
     
     
       3. The method of claim 2 wherein the solid block rinse aid comprises about 80-90% by weight surfactant. 
     
     
       4. The method of claim 1 wherein the polyether compound is a polyoxyethylene/polyoxypropylene glycol polymer. 
     
     
       5. The method of claim 4 wherein the polyoxyethylene/polyoxypropylene glycol polymer has the structure (PO)hd n(EO) n  (EOPO) n  (PO) m  (EOPO) n  (EO) n  (PO) n  where PO represents propylene oxide units and EO represents ethylene oxide units, EOPO represents a random mixture of ethylene oxide and propylene oxide units at a ratio of EO to PO of about 6:100 to 9:100, m is an integer from 1-3, each occurrence of n, independently, is an integer from 17-27, and where the polymer has an average molecular weight of between about 3,500-5,500 and a weight percent of EO of about 25-35%. 
     
     
       6. The method of claim 1 wherein the solid rinse aid further comprises an effective dispensing rate modifying amount of a urea compatible additive. 
     
     
       7. The method of claim 6 wherein the additive comprises a low molecular weight substantially water-insoluble compound. 
     
     
       8. The method of claim 7 wherein the additive comprises an alkanolamide compound, lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, a silicone dimethyl polysiloxane compound, a free acid of an organic phosphate ester compound, or mixtures thereof. 
     
     
       9. The method of claim 7 wherein the additive comprises a cetyl alcohol phosphate ester compound. 
     
     
       10. The method of claim 6 wherein the additive is present in the solid rinse aid at up to about 30% by weight of the solid rinse aid. 
     
     
       11. The method of claim 10 wherein the additive is present in the solid rinse aid at up to about 5% by weight of the solid rinse aid. 
     
     
       12. The method of claim 1 wherein the polymeric synthetic organic surfactant is an aliphatic alcohol alkoxylate or an aliphatic carboxylic acid alkoxylate.